Juraj Cintula, appearing in court in the central city of Banska Bystrica, has been indicted on terrorism charges.
"Long live democracy, long live free culture," Cintula shouted on Tuesday as he arrived at the Specialised Criminal Court.
The 72-year-old is accused of opening fire on Fico on May 15, 2024, as the prime minister greeted supporters following a government meeting in the town of Handlova, 140km northeast of the capital.
Cintula was immediately arrested and was ordered by a court to remain behind bars.
If convicted, he faces life imprisonment.
Fico was shot in the abdomen and was transported to a hospital in nearby Banska Bystrica.
He underwent a five-hour surgery followed by another two-hour surgery two days later.
He has since recovered.
Cintula originally was charged with attempted murder.
Prosecutors later dropped that charge and said they were instead pursuing the more serious charge of engaging in a terrorist attack, based on evidence the investigators obtained, but they gave no further details.
Government officials initially said they believed it was a politically motivated attack committed by a "lone wolf", but announced later that a third party might have been involved in "acting for the benefit of the perpetrator".
Fico previously said he "had no reason to believe" that it was an attack by a lone deranged person and repeatedly blamed the liberal opposition and media for the assassination attempt.
Fico has long been a divisive figure in Slovakia and beyond.
He returned to power for the fourth time after his leftist Smer, or Direction, party won the 2023 parliamentary election after campaigning on a pro-Russia and anti-American message.
His critics have charged that Slovakia under Fico has abandoned its pro-Western course and is following the direction of Hungary under Prime Minister Viktor Orban.
Thousands have repeatedly rallied in the capital and across Slovakia to protest Fico's pro-Russian stance and other policies.
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